1. Field of the Invention
The present invention relates to an image display apparatus with a plurality of micromirrors that are arranged in a matrix and can change angles of reflection.
2. Description of the Related Art
An example of an image display apparatus employing micromirrors that can turn on or off (reflect or not reflect light into a projection lens) by individually changing the slope of each micromirror, i.e., angles of reflection is conventionally disclosed in Japanese Laid-open Patent Application No. 1996-0014691.
In the image display apparatus configured as shown in FIG. 8, light emitted from a light source (not shown) is reflected from a condensing mirror (not shown), is separated into color components by a color filter (not shown), and incident on a light tunnel (not shown). The light exiting the light tunnel passes through a relay lens system 101 and is then incident on a total reflection prism 102. The light reflected from the total reflection prism 102 passes through cover glass 103 and is incident on a reflective display 104. The reflective display includes a plurality of micromirrors 104a arranged in a matrix. Each of the micromirrors 104a changes the slope, and thus an angle of reflection of each of the micromirrors is independently changed. The micromirror 104a is turned on, when light is reflected toward a projection lens 105. The micromirror 104a is turned off, when the light is reflected in a different direction than toward the projection lens 105. By controlling the on/off state of the micromirror 104a, a desired image can be projected by the projection lens 105 for display.
However, the image display apparatus using the total reflection prism 102 becomes bulky and expensive due to the increased number of lenses in the relay lens system 101 and the high price of the total reflection prism. The image display apparatus also suffers degradation in illumination efficiency as light passes through optical surfaces of the relay lens system 101 with a large number of lenses and the total reflection prism 102 in an optical path.